I've used V7 of MTW Pro for some years and got used to being able to run the same macro from a hotkey, perhaps several times per second while gaming. V8 seems to be different in that once a macro is run, it ignores hotkeys for some considerable period of time - perhaps half a second. In gaming, half a second latency is simply not acceptable. If this is a functional change to derive some benefit, I'd like to request some sort of an option so that when I press a hotkey, the associated macro is run and not ignored.

I'd go back to V7, however since I purchased and installed V8, it seems to have made V7 impossible to use on my system. V7 won't load a macro file, even the demo ones. Some macro files make V7 exit. I've tried uninstalling both versions, rebooting and installing V7, but to no avail. So for now I'm stuck on V8 with this laggy hotkey issue. any solutions or workaround much appreciated.

make sure that you have "Start macro after all hotkey keys are released" option on your hotkey trigger unchecked.
Other tweak you could try is to make the macro to have "How to send macro text to target application..." option (which can be changed globally in Program settings or individually for each macro) set to "as keystrokes".

As for the V8 versus V7, it is not possible to open in V7 macro files created/modified in V8. So if you want to go back to V7 then you need to use a backup copy of your macro file that was automatically created before V8 saved the V7 macro file.